Canning and Fish Packaging Technology

Unit 4 - Thermal process for canned foods

4.10.1.2.Direct heat exchangers
The Product and heating medium are in direct contact. The only heating medium applicable to food is steam which condenses in the product. In this there are two alternatives.

• Injection of steam into the product
• Infusion of product into the steam

Other methods of heat exchange involve dielectric heating and mechanical friction heating where heat is directly transferred to the product.